Charper732

I have another thread about finding the main bearing going out. I caught it early and was able to grind the crank .0010 and go with oversize bearings. The car is back together but the oil pressure it not where it should be. Idle is okayish, I was at 19psi at idle before mains started going out and now its at 21psi at 172 degrees. But when the RPMs rise the oil pressure only goes up to 60-65psi. I've only gone up to 4-4.5k rpm but this is very disturbing as before anything over 3k gave me 80psi of pressure. I set clearances between .001 and .0015

Any ideas? The oil pump looked fine so I did not replace it when I was in there.

Also, currently having a major issue bleeding the coolant system. I spent 2 hours on it tonight and cannot figure it out. I drive it, pull over, shut it off and crack the bleeder and a ton of air comes out but no coolant is ever needed to be added to the radiator. The heat blows hot as hell when 4k or above but when it drops to idle the heat goes cold. It's not leaking or burning coolant so I don't know what the hell the issue is. Is it possible the HG is leaking from atmosphere in allowing air into the system but not coolant to leak out?

Edit: to add the coolant issue. If I stop and just let the car idle the fans will bring the temps down from 200 into the low 190s. Ill shut the car off and crack the bleeder...no pressure. Only happens if I let the car sit idle for awhile though. If i crack it after a short drive there is a lot of pressure

starchland

Did you check the oil pump per FSM?

Charper732

yes

jyeung528

did you do a coolant system pressure test? maybe you have a bad radiator cap, try replacing that. i wouldn't drive it if the heat goes cold.

Charper732

well figured out both issues today. Coolant system was as simple as a hose clamp not all the way on on a hose near the heater core.

The oil pressure issue is a bit more interesting. I am running a filter relo and oil cooler. A while back I had accidentally swapped the lines off the relo plate but I noticed it instantly on my oil pressure gauge and shut the car off and swapped the lines. The valve on the aftermarket filter I was using stops flow completely if oil is going the wrong direction.
Fast forward to today, I am running OEM honda filter. Apparently I had the lines on wrong again, but oem honda filters allow some flow in the wrong direction. I saw 60psi of pressure on cold start so I had assumed all was fine. So today I swapped the lines just to see if there was a difference....85psi on cold start. I am seeing 18-21psi at 200 degrees at idle and running a steady 77 psi at 200 degrees anything above 3k. Mystery solved.

Still not sure how the hell the manual calls for 36psi at warm idle. I am running rod/main bearing clearances on the looser side, but still within oem spec. I know running an oil cooler wouldn't lower the pressure THAT much.

That bit about oem filter compared to aftermarket is a bit of golden information though. I've heard of guys doing the same thing with the lines and toasting a motor.

windhund116

Was there a reason you decided to run the bearings on the looser side of spec?

Thanks!

Charper732

Boosted

windhund116

Wouldn't you want the tolerance tighter, within OEM specs? To maintain oil pressure at high revs and heat?

rrounds

Not in most cases, on a high HP engine most are built on the loose side. You do have to adjust the oil pressure for your build which is not hard to do. If you can't find a high volume pump you can shim the stock oil pressure relief spring for more oil pressure. If you shim the spring it won't raise the oil pressure at idle but as the rpm's go up the stock oil pump will put out more oil and pressure before going into by-pass. You can also run a little thicker oil to help with the oil pressure but I would adjust the oil pump to put out more pressure. At least 10 psi per 1000 rpm is what I shoot for.

ROD

R-Poizon

Very interesting.

Im building a turbocharged engine too but I spec the clearances on mains 0.002 and rods.0.0021.

I will do that oil pump mod. What was the thickness of the shim you used on your pump? Do you remember ? I will have to start from there and then make it more thicker I think. Is there any high volume oil pump outhere ?